写了这一句GridView gv = new GridView();using应该怎样引用。谢谢。

Question

       SqlConnection conn = new SqlConnection();
            string connToMaster = "Server=.\\sqlexpress;DataBase=master;Integrated Security=true";
            string connToDb = "Server=.\\sqlexpress;DataBase=test1;Integrated Security=true";
            string createDbStr = "Create database [test1]";
            string createTableStr = "create table example ([id] int primary key,[name] Nchar(5))";
            string insertStr = "insert into example values(1,'Mike')";
            string selectStr = "select * from example";
            SqlCommand cmd = new SqlCommand(createDbStr, conn);            conn.ConnectionString = connToMaster;
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();            conn.ConnectionString = connToDb;
            conn.Open();
            cmd.CommandText = createTableStr;
            cmd.ExecuteNonQuery();
            cmd.CommandText = insertStr;
            cmd.ExecuteNonQuery();
            conn.Close();            cmd.CommandText = selectStr;
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            DataTable dt = new DataTable();
            da.Fill(dt);            GridView gv = new GridView();    //???
            Form1.Controls.Add(gv);
            gv.AutoGenerateColumns = true;
            gv.DataSource = dt;
            gv.DataBind();
        }
报错：找不到类型或命名空间名称“GridView”(是否缺少 using 指令或程序集引用?)

Answer 1

using( SqlConnection conn = new SqlConnection())
{
 //....
}

Answer 2

用了using System.Web.UI.WebControls;
报错：命名空间“System.Web”中不存在类型或命名空间名称“UI”(是缺少程序集引用吗?)